Men’s Casual Suits vs Formal Suits: What’s the Difference?

To the uninitiated, the differences between a men’s casual suit and a more formal one can appear very subtle indeed. Often to the point of creating confusion. Dressing for a formal occasion but unsure whether you’re doing it right? Wanting to look more casual, but don’t know how? Our guide to the differences between men’s formal and casual suits will have you up to speed in no time.

How to Tell the Difference Between a Formal and Casual Suit for Men?

Single or Double Breasted?

Men’s suit jackets typically come in one of two main styles; single or double-breasted. In practice both can be worn in formal and informal situations, depending on everything else that’s going on with the suit and its accessories.

All other things being equal, though, a double-breasted suit is the more formal of the two styles. So if you’re looking for a men’s casual suit, and really want to avoid anything too dressy, the single most important step you can make towards achieving a causal style is simply opting for a single-breasted jacket.

On the flip side, if you’re out to create a smarter and more elegant impression, merely the act of choosing a double-breasted suit will already take you half of the way there.

As we’ll see, though, the difference between a formal and casual suit is more about the combined effect of a number of different elements than any single design feature. So don’t feel like you are forced to choose one particular style of jacket if your personal preference would actually be to go with the other. It’s more about the total look than any single element.


As with the front fastening (above), there are two main types of lapel that you’ll see in everyday use: notch and peak (there’s also the shawl collar, but that’s a whole other story and not a design you’ll see very often in the wild). Of the two styles, a peak label is undoubtedly the more formal looking. And, not coincidentally, it is also the standard type of lapel that you’ll find on a double-breasted jacket.

Meanwhile, notch lapels are more commonly seen than peaks. Unsurprisingly, then, notch lapels are also considered more causal. To be clear, you can certainly make a very formal impression in a jacket with notch lapels, but this will depend a great deal on how you wear it.

In short, if your goal is to put together an appropriate look for a formal occasion, peak lapels will give instant credibility. Meanwhile, although a jacket with notch lapels can also appear very formal if all the other details combine to make it so, notch lapels are more versatile than the peak in that they can easily be dressed down, too. As a general rule, though, men’s casual suits will always feature notch lapels.

Get Your Casual Made To Measure Suit

Aside from the shape of lapels, the final thing to mention when considering casual vs formal suits is lapel width. Skinny lapels are clearly more casual. So if trying to put together a relaxed look, you will probably want to avoid truly wide lapels. However, just keep in mind that looser, wider fits have come to dominate the catwalks over recent seasons, so the extreme skinny look is clearly on its way out of fashion.


Single-breasted suits come in one, two, three (and occasionally even four) button varieties. A two-button fastening is widely acceptable in most professional and social situations – either formal or informal.

Don’t take this as a hard, fixed rule, but generally the more buttons a jacket has, the more likely it is to look formal. A single-button suit, by contrast, somehow always feels much more casual.

It’s the same situation with double-breasted suits; four buttons feel quite relaxed, while six buttons create a primmer, more ceremonial air.

Of course, just because you have all these buttons doesn’t mean you’ll necessarily want to use them. In fact, the bottom button on a two or three-button single-breasted suit should never be fastened anyway. But beyond this, you can influence how smart or casual your three-button suit feels, simply by deciding whether or not to fasten the top button. Hint; two closed buttons usually look more conservative.

Also, consider that the type of buttons a suit has will equally influence the impression it makes. Mother of pearl will always look smart, especially when in a similar color to the suit fabric. And brass will look equally formal on a double-breasted blazer. But less conventional materials such as wood, or even otherwise quite classic buttons in a contrasting color, will be more appropriate on men’s casual suits.


Unsurprisingly, most men’s formal suits come in rather reserved colors such as dark blue and charcoal gray. Meanwhile, men’s casual suits are free to come in a much wider range of unusual, and even downright eccentric, colors and patterns.

It’s not just about the color, though. The type of cloth also plays a part in deciding whether a suit can be considered smart or casual. On the arc of formality, dark woolen fabrics in plain or pinstripe weaves are about as safe and smart as it gets; then come windowpane check and “country” fabrics like tweed; followed by suits in lighter summer-weight cloth such as fresco di Lana, cotton, or linen; and finally it’s a free-for-all, with whatever fantastical colors or crazy patterns you can dream of.

Lastly, also consider that a softer, more flowing, the fabric will tend to feel more casual than one that hangs stiffly.


Another important element that can help make the difference between a formal and casual men’s suit is its cut. Regardless of the number of buttons a suit jacket has, a high-buttoning design will tend to feel a little more formal than the looser low-buttoning style of, say, a late ‘80s Armani suit.

Get Made To Measure Formal Suit

Also, consider the length of the jacket. In recent years many men’s suits have come with much shorter jackets than would have been acceptable in the past. These can certainly be fine in more casual situations. But as any shortening of the jacket will upset the classically balanced proportions of the suit, it is not really a look that is acceptable in more conservative contexts. Which is to say that, if you are looking for a formal suit, you should stick to ones featuring a longer, more traditionally-cut jacket.


To a large degree a suit gets its flattering shape from the use of canvas, or some other reinforcement material, stitched into the jacket around the chest. Regardless of whether the jacket uses traditional hand-sewn canvas or modern interfacing to create structure, though, the stiffer and bulkier this material is, the more formal an impression it will make.

To cite Armani again, a big part of what was so revolutionary about what he did to the suit in the 1980s was to make it a much softer and more casual item. He achieved this, in part, by doing away with much of the canvasing previously used in classical tailoring. Thus the jacket lost a lot of its traditional stiffness.

This means that if you’re looking for a more formal suit – for a wedding for example – then you should stick to classic fully-canvased construction. But for a more casual look, a softer, lighter silhouette is the way to go.


Most suits you’ll see worn today feature flap pockets. Some suits – particularly double-breasted ones – come with simpler welted pockets. Occasionally you’ll also encounter Neapolitan-style patch pockets. Of the three, flap pockets will make the most formal impression; closely followed by welted pockets. Patch pockets, on the other hand, create a much “sportier” casual look.

It’s Not What You Wear, It’s the Way that You Wear It

1970s punks were partial to a nice suit – albeit ones salvaged from charity shops. But when you wear a suit covered in pins and other unconventional decorations and combine it with a ripped t-shirt and a pair of heavy para boots, clearly any discussion about lapel sizes and button fastenings becomes purely academic.

We’re not suggesting that you will necessarily want to spraypaint your hair into a mohawk hairstyle before stepping out in your new custom suit. But it is worth keeping in mind that the other items you combine your suit with will make a significant difference to the overall impression you create when wearing it. Even a very formal suit can be dressed down to look more casual if desired.

For example, the same navy blue suit that looked so smart when paired with a shirt, necktie, and Oxford shoes in the daytime, could just as easily be worn in the evening if combined with a t-shirt and crisp white leather sneakers. This can be a great solution when traveling; allowing you to pack light, yet get the most out of the few items of clothing you bring with you by making them double up for both formal and casual situations.

Just keep in mind that it will always be more difficult to make the trick work in the other direction. I.e. if you start out with an inherently very casual suit (see all the points above), no amount of clever accessorizing will ever make it acceptable for a truly formal occasion.

Men’s Casual Suits vs Formal Suits: The Last Word

As we’ve just seen, the difference between a man’s casual suit and the more formal variety doesn’t come down to any single decisive feature but depends on the general impression created by a whole range of smaller details working together. Individually, these details may not be enough to swing the effect one way or the other, but collectively they can radically alter the end result.

Get Your Made To Measure Casual Suit Today!

For example, on the spectrum of suit formality, a six-button double-breasted peak lapel suit in dark navy is a full-fat #10. Whereas a one-button, single-breasted, notch lapel suit in canary yellow will get an empty zero for smartness. Between these two extremes, though, lies an entire range of sartorial nuance. And as you now have a clear idea of precisely what details to look out for, you should have no difficulty in telling a men’s casual suit from a more formal one when you come across it!

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